AC Delco Dexos low TBN

[jkhawaii]

I recently sent a sample out to Black Stone from my car that has been using delco Dexos and the TBN reported 0! the OLM was at 7%. the last sample I sent out was a few years ago at that time I was using Goodwrench 5w30 SM and TBN was 1.5. The wear numbers and viscosity looked better with the Dexos but the TBN was low. should I be concerned about the TBN?

 

[HTSS_TR]

Yes. TBN of 1.0 is low, I would like to have TBN not less than 1.5-1.6. You may need to change your oil when OLM went down to 15-20%, then do another UOA to see what is the TBN at that OCI.

 

[Donald]

Remember the OLM used a bunch of metrics to calculate the oil life, not TBN.

Just to be sure, did B/S say your TBN (in words) was "zero" or "one point zero"?

Your post says "0!".

 

[Artem]

Title is wrong. If the TBN was ZERO, that's not considered low TBN, that's NO TBN left.

 

[jkhawaii]

Atrem. Your right the title of NO TBN LEFT may have been more appropriate. I know a TBN of 0 would be far to low but Its hard to believe. DEXOS was supposed to be a more robust oil than the old SM Dyno I used before. Maybe TBN is not as important as we are led to believe?

 

[ABerns]

What vehicle was the oil run in? The direct injections beat up oil pretty quickly, so it wouldn't surprise me that the semi-synthetic dexos oil didn't last the entire OCI.

Then again, you said the Goodwrench oil had a TBN of 1.5 - same car, I assume? I am surprised Goodwrench held TBN better than dexos. How were the wear metals?